315 research outputs found
Correlating low energy impact damage with changes in modal parameters: a preliminary study on composite beams
This paper is an experimental study of the effects of multi-site damage on the vibration response of a composite beam damaged by low energy impact. The variation of the modal parameters with different levels of impact energy and density of impact is studied. Specimens are impacted symmetrically in order to induce a global rate of damage. A damage detection tool Damage Index is introduced in order to verify the estimation of damping ratios. Design of Experiments is used to establish the sensitivity of both energy of impact and density of damage. The DOE analysis results (using natural frequency only) indicate that impact energy for 2nd, 3rd and 4th bending modes is the most significant factor contributing to the changes in the modal parameters for this kind of symmetrical dynamic test
IL-6 and IL-1 beta responses to a carbohydrate-electrolyte drink in orienteering athletes
Background: This study was conducted to determine acute effects of carbohydrate-electrolyte (CHO-E) found in sports drinks, ingested just before an orienteering competition, on the levels of plasma IL-6 and IL-1 beta cytokine.Material and methods: The study was conducted in a randomized, double-blind design, including 23 elite orienteering athletes who volunteered to participate. Following the collection of resting specimens of blood, the experimental group (n = 12) was administered a sports drink containing CHO-E, while the placebo group (n = 11) was administered 500 ml of plain water. The subjects were asked to finish the orienteering competition.Result: IL-1 beta level in the 24th hour after the competition was found to be significantly lower than in precompetition and 2 hours after the competition in the placebo group (p 0.05).Conclusion: A drink containing CHO-E might have stopped muscle contraction-associated cytokine production by increasing the tissue stability of the muscles, compensating the loss of fluid and electrolytes from athletes' bodies
Tools for the co-designing of housing transformations: A study on interaction and visualization modes
In this paper we present and assess tools for visualizing architectonic modifications of existing housing in co-design projects with inhabitants. These tools should enable inhabitants to explore and understand design variations of alterations of their houses. This contribution is part of ongoing research on the use of artificial realities for supporting the transformations of existing housing in architectonically responsible ways. Such transformations may be needed after the delivery of housing, say after five years or later, due to changed regulation, the need of updates or changed living conditions of inhabitants. For arriving at architectonically responsible transformations, we use shape grammar system for defining possible modifications of the housing. For empowering inhabitants to understand and explore these modifications to their housing, we develop a transformation grammar tool—MyChanges—to visualize the modifications by three visualization modes, from fully immersive to non-immersive. Interviews and tests with real inhabitants were performed, and preliminary conclusions show that a tool like the MyChanges would have a good acceptance among inhabitants.info:eu-repo/semantics/acceptedVersio
Pinealectomy Increases and Exogenous Melatonin Decreases Leptin Production in Rat Anterior Pituitary Cells: an Immunohistochemical Study
Summary Melatonin, the main hormone of the pineal gland, informs the body about the environmental light and darkness regimen, which in turn contributes to the photoperiodic adaptation of several physiological functions. Leptin, the hormone secreted mainly by adipocytes and some other tissues including the pituitary, informs the brain about the mass of adipose tissue, which plays an important role in energy homeostasis. Melatonin has been shown to decrease circulating leptin levels. It is currently not known whether melatonin has an effect on leptin synthesis in the pituitary. The aim of this study was to immunohistochemically examine the effects of pinealectomy and administration of melatonin on leptin production in the rat anterior pituitary. The pituitary samples obtained from 18 male Wistar rats including sham-pinealectomized, pinealectomized and melatonin-injected pinealectomized groups were immunohistochemically evaluated. Immunostaining of leptin was moderate (3+) in sham-pinealectomized rats, heavy (5+) in pinealectomized rats and low (1+) in melatonin-treated pinealectomized rats, respectively. The present results indicate that pinealectomy induces leptin secretion in anterior pituitary cells, and this increase of leptin synthesis can be prevented by administration of melatonin. Thus, melatonin seems to have both physiological and pharmacological effects on leptin production in the anterior pituitary of male rats
Scrotal calcinosis due to resorption of cyst walls: a case report
<p>Abstract</p> <p>Introduction</p> <p>Scrotal calcinosis is a rare benign entity defined as the presence of multiple calcified nodules within the scrotal skin. There are controversies about the origin of this entity. In fact, it is still debatable whether scrotal calcinosis is an idiopathic growth or dystrophic calcification of dartoic muscles. It is also unclear whether scrotal calcinosis originates from inflammation of epidermal cysts affected by mild to moderate inflammation of mononuclear cells, from foreign body granuloma formation followed by resorption of cyst walls or from eccrine epithelial cysts.</p> <p>Case presentation</p> <p>We report a 41-year-old male Turkish patient presenting with a 10-year history of scrotal tumours increasing slowly in size and number. Histopathologically, there was no epithelial lining around the calcified nodules, but there was fibrosis adjacent to atrophic stratified squamous epithelium.</p> <p>Conclusion</p> <p>Results of histopathological examinations suggested that scrotal calcinosis might have been due to resorption of cyst walls. Surgery remains the key for this problem. In cases of non-massive scrotal calcinosis, like the case presented here, excision of the nodules from the affected part of the scrotal wall and repairing the defect with horizontal stitches offer good cosmetic results without relapse.</p
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Bio-efficacy of hydroxy-selenomethionine as a selenium supplement in pregnant dairy heifers and on the selenium status of their calves
This study aimed to determine the effects of supplementing pregnant heifers with the organic selenium source 2-hydroxy-4-methylselenobutanoic acid (HMSeBA) during last eight weeks of pregnancy on dam and calf Se status. A total of 42 in-calf heifers were recruited to the study and randomly allocated to one of three treatments; a negative control (Con), sodium selenite (NaSe) or HMSeBA. Animals were blocked by body weight, body condition score, and expected calving date prior to treatment allocation. Following enrollment all animals underwent a seven week wash-out period after which they received their respective supplements, topped dressed daily onto a basal diet for the last eight weeks of pregnancy. Heifer blood samples were taken at weekly intervals from enrollment until two weeks before expected calving date, and as soon as possible after calving for determination of whole blood glutathione peroxidase activity (GSH-Px) and plasma selenium (Se) and malondealdehyde (MDA) concentrations. Selenized amino acids were determined in plasma samples taken at three weeks pre-calving. A colostrum sample was taken as close to parturition as possible for determination of colostrum total Se, selenized amino acid, and Immunoglobulin G (IgG) concentration. Calves were blood sampled as close to birth as possible for determination of whole blood GSH-Px activity and plasma Se and MDA concentration. Differences in whole blood GSH-Px activity did not become apparent until calving; GSH-Px activity was lowest in Con heifers (P < 0.05) but similar between NaSe and HMSeBA. Plasma Se was lowest in unsupplemented heifers and greatest in those supplemented with HMSeBA (P < 0.001) and this was attributable to greater selenomethionine concentrations in the plasma of HMSeBA heifers (P < 0.01). Colostrum Se was lowest in Con heifers and greatest in HMSeBA (P < 0.001), the greater Se concentration of HMSeBA heifers was attributable to a greater proportion of total Se comprising selenocysteine (P = 0.061), the reason for this is not known. There was no effect of supplementation on colostrum IgG concentration. Plasma Se was lowest in those calves born to Con heifers and greatest in those born to HMSeBA heifers (P < 0.001). There were no effects of treatment on calf whole blood GSH-Px activity or plasma MDA concentration. The enhanced Se status associated with HMSeBA supplementation is likely a consequence of selenomethionine supply and may confer benefits to both the dam and her calf post-partum
Effect of grain and secondary phase morphologies in the mechanical and damping behavior of Al7075 alloys
The present study evaluates the role of the microstructure in the static and dynamic mechanical behavior of as-cast Al7075 alloy promoted by ultrasonic treatment (US) during solidification. The characterization of samples revealed that US treatment promoted grain and intermetallics refinement, changed the shape of the intermetallic phases (equilibrium phases of soluble M and/or T (Al, Cu, Mg, Zn) and their insoluble Al-Cu-Fe compounds) and lead to their uniform distribution along the grain boundaries. Consequently, the mechanical properties and damping capacity above critical strain values were enhanced by comparison with values obtained for castings produced without US vibration. This results suggest that the grain and secondary phases refinement by US can be a promising solution to process materials to obtain high damping and high strength characteristics.This research was supported by FEDER/COMPETE funds and by national funds through FCT - Portuguese Foundation for Science and Technology and was developed on the aim of the research Post-Doctoral grant SFRH/BPD/76680/2011. Also, this work has been supported by the FCT in the scope of the project: UID/EEA/04436/2013.info:eu-repo/semantics/publishedVersio
Endoplasmic spreading requires coalescence of vimentin intermediate filaments at force-bearing adhesions
10.1091/mbc.E12-05-0377Molecular Biology of the Cell24121-30MBCE
Keeping the Vimentin Network under Control: Cell–Matrix Adhesion–associated Plectin 1f Affects Cell Shape and Polarity of Fibroblasts
Mature focal adhesions and fibrillar adhesions act as anchorage sites for vimentin filaments, with plectin isoform 1f being the crucial linker protein. Plectin serves as a nucleation and assembly center for the de novo formation of vimentin networks. Anchored vimentin creates a resilient cage-like core structure that affects cell shape
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